Switchmode LED flashlight upgrade

When [Neelandan]’s cheap flashlight’s internal rechargeable battery died, he scrounged for a replacement. Ultimately, the brightness of the light suffered with his new battery, taken from an old cell phone since he had dropped the voltage a bit. Upon inspection he saw that he would have to swap the individual resistors for each lamp to get the desired brightness again. This wasn’t really acceptable as he would have to repeat the process if he used another re-purposed battery with different specs. Instead, he added a new circuit to supply constant brightness until the voltage drops below 2.7 volts. We love to see hardware resurrected, even if it is just a cheap LED flashlight.

loanshark: Sounds to me like you need to update yourself when it comes to LED tech ;) Treat yourself to a new flashlight from a company like Fenix for example. They make decent flashlights at decent prices and it will blow your current one away.

or you could rip out the cheap LEDs and replace with a couple of 10W ones.
a suitable lens can be had from a broken HID lamp in many high performance cars, often the whole unit is scrapped for a cracked tube or glass even though the lenses and electronics are fine.